Many products are wrapped in a heat-shrinkable film which is subsequently shrunk by the application of heat. Often the enclosed product is visible through this film and the appeal to the prospective purchaser is somewhat dependent on the package appearance. The film is typically preprinted with the producer's name, producer's logo and other information of interest to the consumer. Efforts have been made in the past to improve the package being displayed for sale by assuring that the film appears with few or no wrinkles and is preferably tightly fitted around the enclosed product.
Some examples of known methods for the shrinking of heat-shrinkable film are disclosed in U.S. Pat. No. 5,062,217 for a SELECTIVE SEQUENTIAL SHRINK APPARATUS AND PROCESS; U.S. Pat. No. 5,193,290 for an APPARATUS AND METHOD FOR SEQUENTIAL SHRINKING OF PACKAGING FILM; and U.S. Pat. No. 5,398,427 for an APPARATUS AND METHOD FOR DIFFERENTIALLY SHRINKING SELECTED PORTIONS OF HEAT SHRINKABLE FILM WRAPPED AROUND A PRODUCT, all to the present applicant, the teachings of which are incorporated herein by reference.
Recent changes in the laws and regulations governing packaging and labelling of meat products require that each package be marked with safe handling and cooking procedures, and that the print be clear and readable. In the interest of compliance and consumer relations, processors of poultry parts, in particular, have been seeking a package print which after being shrunk exceeds the readability requirement and is sharp and bold. To achieve that level of packaging print quality, it is both necessary to shrink the preprinted heat-shrinkable film without forming wrinkles and to cause the printed portions to be protected from heat-induced discoloration or distortion.
In another aspect of the prior art, a widely used method of film wrapping a product results in a longitudinal bottom seam and a transverse seam at the leading and trailing ends of the package. The present invention is directed to this form of packaging. As one embodiment of this form of packaging and in response to the new laws and regulations, applicant's copending patent application Ser. No. 08/225,822 filed Apr. 11, 1994, entitled METHOD OF MAKING A FILM WRAPPED PRODUCT HAVING AN OFF-CENTER SEAM, now U.S. Pat. No. 5,421,139, teaches a method for off-setting the bottom longitudinal seam to better facilitate the placement of printed information regarding storage, cooking instructions, etc.
It is therefore an object of this invention to provide an apparatus and method for the shrinking of heat-shrinkable film wrapped around a product which results in a wrinkle-free finished package appearance.
A further object of the invention is to provide an apparatus and method for the shrinking of preprinted heat-shrinkable film wrapped around a product in a manner which minimizes the discoloration and distortion of print on the film.
An additional object of the invention is to provide an apparatus and method for the shrinking of preprinted heat-shrinkable film wrapped around a product without causing wrinkles.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.